1. Yes, it is a paid App. But it is open source as well in github. I did paid but after installing Android Studio I found that you can compile and deploy it by yourself. It is just $1.99.
2. Yes. It is manual sync. That's why we need to hack into the code and wake it up and force it to sync. In my case: I want my WSJ daily download from Calibre at 6AM and then sync by ownCloud desktop App in my Mac.
3. Sync from Calibre to ownCloud server is easy: put the Calibre folder in PC/Mac as ownCloud folder. In desktop file sync is automatic.
4. It takes time. That's why I need help/suggestions.
TBH, I know nothing about Objective C and iOS app development until I feel fed up with AT&T asking me to give up my grandfather unlimited data plan in order to use their hotspot on my iPhone. That is how I start my iOS tethering App (
https://github.com/rickyzhang82/tethering) several years ago when I'm single.
Now I have two year old. My time is very limited. If any Android expert here is interested in my proposal, please let me know. I can start a bounty program and let community decide how much does it worths.
But if no one is interested in it, I can do it by myself. But that takes time as you suggest.